What is approach ramp?

An approach ramp is the sloping section of yard that leads vehicles down to a recessed dock, lowering the trailer so its bed meets a warehouse floor built near ground level. Gradient, drainage at the foot of the slope and retaining walls are the main design points.

What is curtain-sider?

A curtain-sider is a trailer or rigid lorry with fabric side curtains that slide back so goods can be loaded from the side by forklift, as well as from the rear at a dock. Bed heights vary between models, which affects the leveller working range a site needs.

What is edge-of-dock leveller?

An edge-of-dock leveller is a compact leveller fixed to the face of an existing dock, with no pit, that bridges small height differences between dock and trailer. It is a lower-cost option for docks with consistent vehicles but has a much shorter working range than a pit leveller.

Loading Bay Glossary | Loading Bay Doors

Approach ramp: An approach ramp is the sloping section of yard that leads vehicles down to a recessed dock, lowering the trailer so its bed meets a warehouse floor built near ground level. Gradient, drainage at the foot of the slope and retaining walls are the main design points. More
Approved Document L: Approved Document L is the guidance on conservation of fuel and power that supports the Building Regulations in England. Volume 2 (2021) sets a limiting U-value of 1.3 W/m²K for vehicle access and similar large doors in new and replacement work. Wales, Scotland and Northern Ireland have their own energy rules. More
Breakaway bottom bar: A breakaway bottom bar is the lower edge of a high-speed fabric door, designed to pull out of its side guides when struck by a forklift or load instead of bending. On many designs it can be reset into the guides without replacing parts, which keeps a busy opening working. More
BS EN 12453: BS EN 12453 is the British and European standard for the safety in use of power-operated doors, setting requirements and test methods. It covers how a powered door must protect people from crushing, shearing and impact, for example through safety edges, photocells and the choice of control mode. More
BS EN 13241: BS EN 13241 is the product standard for industrial, commercial and garage doors and gates. It sets out the performance and safety characteristics a manufacturer must declare, such as resistance to wind load and thermal transmittance, and underpins the UKCA or CE marking of loading bay doors. More
BS EN 1398: BS EN 1398:2009 is the British and European standard setting safety requirements for dock levellers, covering design loads, safety devices such as toe guards and protection against uncontrolled lowering, and information for use. The 2009 edition is current and under review. More
BS EN 1570-1: BS EN 1570-1:2024 is the British and European standard setting safety requirements for lifting tables serving up to two fixed landings, which includes scissor lift tables used as dock lifts. It covers design, safety devices, controls and the information a manufacturer must supply. More
Cable drum: A cable drum is the grooved drum at each end of a sectional door's spring shaft that winds in the lifting cables as the door opens. Frayed cables, or cables that jump off the drum, are common reasons for a door hanging unevenly and need prompt repair. More
Capacity (dock leveller): A dock leveller's capacity is the rated load it is designed to carry, usually stated in kilonewtons or tonnes. It must cover the heaviest laden forklift or pallet truck crossing it, allowing for the extra force of moving loads, so it is chosen from your actual equipment and products. More
Competent person: A competent person is someone with the practical and theoretical knowledge and experience to carry out an inspection or thorough examination properly and spot defects. Under LOLER they may draw up a written scheme of examination, and they must be independent and impartial enough to make objective judgements. More
Curtain-sider: A curtain-sider is a trailer or rigid lorry with fabric side curtains that slide back so goods can be loaded from the side by forklift, as well as from the rear at a dock. Bed heights vary between models, which affects the leveller working range a site needs. More
Deadman control (hold-to-run): A deadman or hold-to-run control makes a powered door move only while the operator keeps the button pressed, stopping as soon as it is released. The operator must have a clear view of the door, so it generally needs fewer added safety devices than impulse or automatic control. More
Dock bumper: A dock bumper is a rubber, or rubber and steel-faced, buffer fixed to the dock face that takes the impact of a reversing trailer. It protects the building, leveller and door, and keeps each trailer at a consistent distance from the dock so shelters and seals work properly. More
Dock height: Dock height is the height of the loading platform above yard level, typically around 1,200 mm in the UK. It is set to suit the most common trailers using the site, with a leveller or lift table bridging the difference for vehicles that sit higher or lower. More
Dock light: A dock light is a lamp, usually on a swing arm, mounted beside the door to light the inside of a trailer during loading. It helps forklift drivers see the load, the trailer floor and anyone working inside, especially in deep trailers and at night. More
Dock seal: A dock seal is a set of foam pads covered in tough fabric, fixed to the sides and top of the door opening, that a reversing trailer compresses against its rear frame. It gives a close seal around the trailer and works best with vehicles of a consistent size. More
Dock traffic light: A dock traffic light is a red and green signal at a bay that tells the driver when to stay put and when it is safe to leave, often with a matching light inside for the loading team. HSE guidance lists traffic lights among the safeguards against early drive-away. More
Door operator: A door operator is the electric motor, gearbox and control unit that powers a loading bay door, usually mounted on the door's shaft or barrel. It is sized to the door's weight and the number of cycles expected, and works with safety devices chosen for how the door is used. More
Double-deck trailer: A double-deck trailer carries goods on two floors to increase the load per journey, using a fixed or moving upper deck and often a lift to reach it. Double-deck trailers can have a low bed height, so the leveller's working range and lip need checking for them. More
Drive-away: A drive-away happens when a vehicle pulls away from the dock while loading is still under way, which can drop a forklift or person from the trailer edge. HSE guidance expects safeguards such as traffic lights, vehicle restraints or the person in charge keeping the keys until it is safe. More
Edge-of-dock leveller: An edge-of-dock leveller is a compact leveller fixed to the face of an existing dock, with no pit, that bridges small height differences between dock and trailer. It is a lower-cost option for docks with consistent vehicles but has a much shorter working range than a pit leveller. More
Flush dock: A flush dock is a loading bay where the dock face lines up with the outside wall of the building. The door sits in the wall, the leveller is just inside it, and the trailer reverses up to bumpers on the wall. It is a common arrangement on UK warehouses. More
Guide rail: A guide rail is the vertical channel at each side of a roller shutter or high-speed door that keeps the curtain aligned as it travels. Damaged, bent or blocked guides are a common reason for a shutter jamming, running noisily or coming out of line. More
Head pad: A head pad is the top section of a dock seal, fixed horizontally above the door opening, which presses against the roof edge of the docked trailer. Fixed or height-adjustable versions are available, and the right height depends on the tallest and lowest trailers using the bay. More
High-lift track: High-lift track is a sectional door track arrangement where the door runs up the wall above the opening before turning back under the roof. It suits buildings with plenty of headroom and keeps the open door higher, clearing lights, sprinklers or racking near the opening. More
HSE and HSENI: HSE, the Health and Safety Executive, is the health and safety regulator in Great Britain, and HSENI, the Health and Safety Executive for Northern Ireland, regulates in Northern Ireland. Both publish guidance on workplace transport, loading and unloading, and work equipment such as dock levellers.
HSG136: HSG136, A guide to workplace transport safety, is HSE's main guidance on managing vehicles at work, including loading bays. It covers site layout, safe reversing and safeguards against drivers leaving the dock too early, such as traffic lights, vehicle restraints and control of keys or paperwork. More
Impulse control: Impulse control lets a powered door open or close fully from a single press of a button. Because the door moves without the operator holding a control, it needs safety devices such as a safety edge and photocells to stop and reverse it if something is in the way. More
Inflatable dock shelter: An inflatable dock shelter is a shelter whose top and side cushions are filled with air by a fan once a trailer is in position, pressing against the trailer's sides and roof. It gives a close seal for chilled and controlled environments and deflates clear of the trailer afterwards. More
Interlock: An interlock is a control link between two pieces of dock equipment so that one cannot operate until another is in a safe state. Examples include a door that cannot open until a restraint is engaged, or a leveller that cannot be used until the door is fully open. More
Lath: A lath is one of the interlocking horizontal strips, usually steel or aluminium, that make up a roller shutter curtain. Laths can be solid, insulated or perforated, and a dented or damaged lath can often be replaced on its own rather than renewing the whole curtain. More
Level-access door: A level-access door is a goods door at yard level, with no dock, that forklifts and pallet trucks drive straight through. It suits side-loaded flatbeds, curtain-siders and vans, and is often paired with a scissor lift table or yard ramp for rear unloading. More
Leveller pit: A leveller pit is the recess formed in the dock floor that houses a pit leveller's frame, platform and hydraulics. It must be the right size, level and structurally sound, and new pits or pit repairs are normally priced separately after a site survey. More
Loading house: A loading house, sometimes called a dock pod, is an insulated enclosure built outside the building that contains a leveller and shelter, so trailers can dock at an existing opening without cutting a pit into the floor. The door then closes against the warehouse floor inside the wall line. More
LOLER: LOLER is the Lifting Operations and Lifting Equipment Regulations 1998, with a Northern Ireland equivalent from 1999. It applies to equipment for lifting or lowering loads, such as scissor lift tables, and requires thorough examination by a competent person at set intervals or to a written scheme of examination. More
Maintenance strut: A maintenance strut is a hinged steel prop under a dock leveller platform that is locked in place to hold the raised platform securely before anyone works or cleans in the pit. It should be used for every inspection, clean or repair beneath the leveller. More
Open dock: An open dock is a loading platform that projects beyond the building wall, with the doors set back at the building line and the platform exposed to the weather unless it has a canopy. It gives less weather protection than a flush dock with a shelter or seal. More
Photocell: A photocell is a light-beam sensor fitted across a door opening that detects a person, vehicle or load in the beam and stops a closing door or prevents it from closing. It is a common safety device on doors with impulse or automatic control. More
Planned preventive maintenance (PPM): Planned preventive maintenance, or PPM, is servicing carried out at set intervals to keep equipment safe and reduce breakdowns, rather than waiting for faults. For loading bays it covers doors, levellers, shelters and restraints, with a written record of the checks made and defects found. More
Power pack: A power pack is the electric motor, hydraulic pump, oil tank and valves that drive a hydraulic dock leveller's platform and lip. Oil leaks, worn seals and failing motors in the power pack are common causes of slow, jerky or uneven leveller movement. More
Projection: Projection is how far a dock shelter or seal stands out from the building wall. It is matched to the dock bumpers and the trailers in use, so a shelter wraps the trailer properly and a seal compresses enough to close the gap without being crushed. More
PUWER: PUWER is the Provision and Use of Work Equipment Regulations 1998, with a Northern Ireland equivalent from 1999. It requires work equipment, including loading bay doors, dock levellers, shelters and restraints, to be suitable, maintained in a safe condition and inspected where deterioration could lead to danger. More
Recessed dock: A recessed dock is a loading bay where the yard is lowered in front of the door, with an approach ramp and retaining walls, so a trailer bed sits level with a warehouse floor built at or near ground level. It is a common way to convert a ground-level door. More
Retractable dock shelter: A retractable dock shelter has fabric side and top curtains on a sprung frame that is pushed back by a reversing trailer and returns when the trailer leaves. The curtains wrap around the trailer, which suits sites where vehicle widths and heights vary. More
Safety edge: A safety edge is a pressure-sensitive strip along the bottom of a powered door that stops and reverses the door if it touches a person or object while closing. It is a key protection against trapping on doors with impulse or automatic control. More
Scissor lift table: A scissor lift table is a platform raised and lowered on a scissor mechanism, used as a dock lift to move goods between yard level and trailer bed height. It is lifting equipment under LOLER, and its design is covered by BS EN 1570-1. More
Sectional door: A sectional door is an overhead door made of hinged horizontal panels, typically 40–80 mm insulated steel, that runs on side tracks and stores under the roof or up the wall when open. It is widely used at docks because it insulates well and seals against the floor and frame. More
Side curtains and top curtain: Side curtains and the top curtain are the fabric panels of a dock shelter that close the gaps beside and above a docked trailer. They are made of tough, flexible material, often with stiffening, and can usually be replaced individually when torn. More
Standard-lift track: Standard-lift track is the most compact sectional door track arrangement, where the door turns from vertical to horizontal just above the opening and stores under the roof. It needs the least headroom but places the open door close to the head of the opening. More
Swap body: A swap body is a demountable load unit that a lorry can leave standing on fold-down legs at a dock and collect later. Its bed height depends on how the legs are set, and it has no wheels for a wheel-based restraint, so different safety checks apply. More
Swing lip: A swing lip is the hinged plate at the front of a dock leveller that swings out and rests on the trailer bed. On a swing-lip leveller it is typically about 400–500 mm long, which suits most everyday rear loading of standard trailers. More
Telescopic lip: A telescopic lip is a leveller lip that slides out from the platform rather than swinging, commonly extending 500–1,000 mm, so the operator can place it precisely. It suits end loading, double-deck trailers and loads stacked tight to the trailer doors. More
Thermal break: A thermal break is an insulating barrier between the inner and outer metal faces of a door panel or frame, so heat or cold cannot pass straight through the metal. It reduces condensation and heat loss, and matters most on cold store and chilled dock doors. More
Thorough examination: A thorough examination is a detailed, systematic check of lifting equipment by a competent person under LOLER, at least every 12 months, or every 6 months for equipment that lifts people and for lifting accessories, unless a written scheme of examination sets other intervals. A written report records any defects. More
Toe guard: A toe guard is the side skirt fitted along a dock leveller platform that closes the gap exposed when the platform is raised above dock level. It stops feet or objects being caught underneath, and HSE guidance notes that guards or skirting may be needed wherever something could be trapped. More
Torsion spring: A torsion spring is the coiled steel spring on the shaft above a sectional door that twists as the door closes, storing energy to counterbalance the door's weight. Springs are designed for a set number of cycles, and a broken spring makes the door heavy or unsafe to operate. More
Trailer bed height: Trailer bed height is the height of a trailer's load floor above the yard, which commonly varies from roughly 900 to 1,600 mm across rigid, curtain-sider, refrigerated, double-deck and container vehicles. The range seen at a site decides the leveller length and working range needed. More
Trailer creep: Trailer creep is the gradual movement of a parked trailer away from the dock, caused by forklifts braking and accelerating inside it. It can open a gap between the trailer and the leveller lip, and is controlled with wheel chocks, vehicle restraints and well-maintained trailer brakes. More
U-value: A U-value measures how much heat passes through a building element, in watts per square metre per kelvin (W/m²K); the lower the number, the better the insulation. In England, vehicle access doors in new and replacement work have a limiting U-value of 1.3 W/m²K. More
UKCA and CE marking: UKCA and CE marking show that a manufacturer declares its product meets the product rules that apply to it. In Great Britain, powered doors and dock equipment may carry either the UKCA or the CE mark. In Northern Ireland, the CE mark, or CE with UKNI, applies.
Vehicle restraint: A vehicle restraint is a device at the dock that holds a trailer's wheel so the vehicle cannot move away until loading is finished. Restraints are commonly linked to traffic lights and interlocked with the door, helping to prevent both drive-away and trailer creep. More
Velocity fuse: A velocity fuse is a valve fitted to a hydraulic dock leveller's cylinder that closes if oil escapes too fast, for example when a hose bursts, so the loaded platform cannot drop. Together with check valves that hold oil in the cylinders, it gives the leveller its freefall protection. More
Vertical-lift track: Vertical-lift track is a sectional door track arrangement where the door runs straight up the wall above the opening without turning under the roof. It needs clear wall height above the opening roughly equal to the door height, and leaves the roof space clear for cranes or services. More
Vision panel: A vision panel is a glazed section or row of windows in a loading bay door that lets daylight in and lets staff see whether a vehicle or person is on the other side. It can be specified with insulated glazing and placed at a height that suits forklift drivers. More
Wheel chock: A wheel chock is a wedge placed against a vehicle's wheel to stop it rolling at the dock. It is a simple measure against trailer creep, but it relies on staff placing it correctly every time and will not stop a driver who decides to pull away. More
Wheel guide: A wheel guide is a steel rail or bollard fixed to the yard on either side of a bay that steers a reversing vehicle into line with the door and leveller. Centred trailers protect shelters and seals and make better use of the leveller's full width. More
Wicket door: A wicket door is a pedestrian door built into a larger sectional door or shutter, so people can pass through without opening the whole door. It is interlocked so the main door cannot move while it is open, and its threshold means a separate pedestrian door is often better on busy routes. More
Wind class: Wind class is the resistance to wind load declared for a door under its product standard, given as a class number where a higher class means the door withstands stronger wind pressure. Exposed coastal or open sites and wide openings usually need a higher class. More
Working range: A dock leveller's working range is how far above and below dock height its lip can rest on a trailer bed while keeping the platform within a safe gradient. Longer platforms give a wider usable range and gentler slopes for pallet trucks and roll cages. More
Yard ramp: A yard ramp is a mobile steel ramp that lets forklifts drive from yard level up into a trailer or container where there is no dock. It is often used for occasional container unloading, and it must be secured to the vehicle and suit the forklift before use.

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